Catalytic synthesis of substituted pyridines from acetylenes and nitriles

ABSTRACT

NOVEL PROCESS FOR THE PREPARATION OF SUBSTITUTED PYRIL DINES COMPRISING CONTACTING AN ALKYL, ALKYLENE OR ARYL SUBSTITUTED NITRILE WITH AT LEAST ONE ACETYLENIC COMPOUND OF THE FORMULA R1-C$C-R7, WHEREIN R1 AND R5 MAY BE H, ALKYL, ALKOXY, ALKENYL OR ARALKYL AT ABOUT 150*C.-600* C. IN THE PRESENCE OF A COBALT CATALYST.

United States Patent Olfice 3,829,429 Patented Aug. 13, 1974 U.S. Cl.260-490 P 4 Claims ABSTRACT OF THE DISCLOSURE Novel process for thepreparation of substituted pyridines comprising contacting an alkyl,alkylene or aryl substituted nitrile with at least one acetyleniccompound of the formula R CECR wherein R and R may be H, alkyl, alkoxy,alkenyl or aralkyl at about 150 C.600 C. in the presence of a cobaltcatalyst.

RELATED APPLICATION This application is a continuation-in-part ofapplication U.S. Ser. No. 1,324, filed J an. 7, 1970, now abandoned.

BACKGROUND OF THE INVENTION Field of Invention This invention is relatedto the synthesis of substituted pyridines which are widely used insynthesis of polymers, pharmaceutical products, pesticides, and manyother classes of valuable products.

DESCRIPTION OF THE PRIOR ART In a process of reacting acetylenes withnitriles in the presence of an alkali metal catalyst yieldingprincipally pyrimidines it was disclosed that in some cases pyridineswere obtained as a minor by-product [1. C. Sauer and W. K. Wilkinson US.Pat. 2,524,479 and T. L. Cairns, J. C. Sauer, W. K. Wilkinson, J. Am.Chem. Soc, 74, 3989 1952)]. Thus, the reaction between benzonitrile andacetylene resulted in 2,4-diphenylpyrimidine in a 29% yield and2-phenylpyridine in only a 1.8% yield. There is no reference tocatalysts other than alkali metals and their alkyl and aryl derivativesor to a process of preparing pyridines at higher yields and withoutobtaining pyrimidines as the major co-product.

SUMMARY OF THE INVENTION According to the present invention there isprovided a process for the preparation of substituted pyridinescomprising contacting at about 150 C. to 600 C. in the presence of acobalt catalyst selected from the group consisting of cobalt metal,cobalt oxides, simple cobalt salts or cobalt complexes in which thecobalt has two or four to six coordinating sites occupied by ligandsselected from the group of hydrogen [1], alkyl [1], carbonyl [4],nitroso [1], phosphine [4], dodecahydrodecaborate [2], enolates of,B-keto esters [3], and 1,3-diketones [31, poly (pyrazolyDborates [2],glyoximates [2], with the proviso that the number of ligands linked toeach cobalt atom does not exceed the bracketed number following eachligand class a nitrile of the formula R -C N, wherein R is alkyl,alkenyl or aryl of up to 20 carbon atoms and may be substituted withcyano, alkoxycarbonyl and carbonyl provided that the resultant nitrileis not subject to rapid homooligomerization or homopolymerization underthe reaction conditions, with at least one acetylenic compound of theformula wherein R and R may be hydrogen, alkyl of up to 10 carbons,alkenyl of up to 10 carbons, aralkyl of up to 10 carbon atoms or alkoxyof up to 12 carbon atoms, provided that the acetylenic compound is notsubject to rapid homooligomerization or homopolym'erization under thereaction conditions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The catalytic process of thisinvention for the synthesis of pyridines by the reaction of nitrileswith at least one acetylenic compound in the presence of a cobaltcatalyst can be depicted by Equation 1:

in which R and R are selected from hydrogen, alkyl of up to 10 carbons,alkenyl of up to 10 carbons, aralkyl of up to 10 carbon atoms or alkoxyof up to 12 carbon atoms, and preferably are hydrogen, alkyl or alkenylof up to 6 carbon atoms. Of course when two ditferent acetyleniccompounds are employed the value of R and/or R will accordingly bedifferent in the two formulae for the acetylenic compound in Equation 1.R may be alkyl, alkenyl or aryl of up to 20 carbon atoms, and preferablyis alkyl, alkenyl or aryl of up to 8 carbon atoms. R may also besubstituted with cyano, alkoxycarbonyl and carbonyl, with the provisothat the resultant nitrile is not subject to rapid homooligomerizationor homopolymerization under the reaction conditions.

Catalysts The cobalt catalyst may be selected from the classes:

(I) Cobalt metal;

(H) Cobalt oxides and simple cobalt salts such as the acetate, formate,citrate, tartrate, propionate, fluoride, chloride, bromide, iodide,nitrate, sulfate stearate and naphthenate.

(III) Cobalt complexes which may be cations, anions, or neutralmolecules, and in which the cobalt has two or four to six coordinatingsites occupied by ligands selected from the group of hydrogen [1], alkyl[1], carbonyl [4], nitroso [1], phosphine [4], dodecahydrodecaborate-[2.], enolates of B-keto esters [3], and 1,3- diketones [3],poly(pyrazolyl)borates [2], glyoximates [2], with the proviso that thenumber of ligands linked to each cobalt atom does not exceed thebracketed number following each ligand class.

' More specifically, alkyl ligands may contain up to 8 carbon atoms,e.g., methyl, ethyl, propyl, benzyl, may be employed. Phosphine ligandsmay be the parent phosphine, PH or alkyl or aryl-containing phosphines,e.g., trimethylphosphine, triethylphosphine, tripropylphosphine,dimethylphenylphosphine, diethylphenylphosphine, ethyldiphenylphosphine,triphenylphosphine, l,2-ethylene-bis-diethylphosphine,l,2-ethylene-bis-diphenylphosphine. Exemplary fi-keto esters are theenolates of ethyl acetoacetate, ethyl 2-methylacetoacetate, methylacetoacetate, ethyl benzoylacetate, ethyl B-ketopropionate, ethyl,6-ketovalerate, and the like. Operable 1,3-diketones include the enolicforms of acetylacetone, propionylacetone, benzoylacetone,dibenzoylmethane, 1,1-dibenzoylethane, 3-methyl-2,4-pentanedione,2,4-hexanedione and homologs.

Examples of poly(pyrazolyl)borates include dihydrobis (pyrazolyl)borate, di'(hydrocarbyl) bis (pyrazolyl) borin which R is an alkyl oraryl of up to 18 carbon atoms, specifically diethylbis(pyrazolyl)borate,dipropylbis(pyrazolyl)borate, diphenylbis(pyrazolyl)borate, and thelike. Glyoximate ligands include glyoxime and dioximes ofdimethylglyoxal, furil, benzil and close homologs.

Where the combination of cobalt and ligand results in an anion, thecounter-ion needed to make a neutral molecule may be any metal cation,preferably an alkali metal, alkaline-earth metal, or Cu+ Cd+ Zn+ Pb+ Sn+Hg, cation, or a quaternary ammonium ion, preferably a tetra(loweralkyl)ammonium ion such as tetramethylammoniurn, tetraethylammonium,n-butyltrimethylam-monium, tetraisopropylammonium and the like. When thecobalt/ ligand combination results in a cation, the counter-anion may behalogen. As noted above, cobalt metal, especially in a form having highsurface to volume ratio, is eifective in catalyzing the reaction of thisinvention. Supported cobalt metal, e.g., on alumina, silica orkieselguhr, is also effective in catalyzing pyridine synthesis. Cobaltoxide, Co O is similarly useful as a catalyst.

A possible explanation of the catalytic efficiency of such a variety ofcobalt compounds, though not limiting the invention, is that none of thematerials added to the reaction mixture is the true catalyst, but thatthe nominal catalysts added are all converted by reaction with theacetylene(s) and/or the nitrile to a unique compound or complex ofcobalt that effects the reaction described. Specific catalysts useful inthe practice of this invention include:

4. bis- 1,2-bis (dimethylphonsphino ethane] cobalt (I) hydride cobaltmetal of 0.5-1.5 micron particle size cobalt(III) oxide.

Acetylene Components The acetylene component must not be subject torapid homooligomerization homopolymerization which is always apossibility in the presence of cobalt complexes, for often suchreactions take precedence over the formation of pyridines. For example,3-butenyne, methyl propiolate and phenylacetylene trimerize tosubstituted benzenes so readily that only small yields of pyridines areobtained. Generally substituted acetylenes in which any substitutent isnon-conjugated with or at least two carbon atoms removed from the CECgroup do not homooligomerize or homopolymerize too rapidly under thereaction conditions of this invention: Specific acetylenes for use inthis invention include acetylene, methylacetylene, dimethylacetylene,butyne-l, pentyne-l, hexyne-l, monoalkylacetylenes having up to 10carbon atoms, e.g., octylacetylene, dial'kylacetylenes having up to 10carbon atoms, e.g., pentyne-2, hexyne-Z, hexyne-3, heptyne-2, heptyne-3,octyne-2, octyne-3, octyne-4, nonyne-2, nonyne-3, nonyne-4, decyne-Z,decyne-3, decyne-4, decyne-S. Other useful acetylenes include3-phenyl-1- propyne, 4-phenyl-l-butyne, S-phenyl-l-pentyne,S-phenyl-2-pentyne.

Nitrile Components Exemplary nitriles, defined above, includeacetonitrile, propionitrile, butyronitrile, l-pentanenitrile,l-hexanenitrile, 2-methy1pentanenitrile, l-heptanenitrile,Z-methylhexanenitrile, 2-ethylpentanenitrile, l-octanenitrile, 2-methylheptanenitrile, 2-ethylhexanenitrile, l-nonanenitrile and itsisomers, l-decanenitrile and its isomers, lauronitrile,hendecanenitrile, hexadecanenitrile, octadecanenitrile, eicosanenitrile,benzonitrile, o-, mp-toluonitrile, 4- phenylbutanenitrile,4-phenylbutanenitrile, p-ethylbenzonitrile,S-ethoxycarbonyl-l-pentanenitrile, S-acetyl-l-pentanenitrile,succinonitrile, glutaronitrile, adiponitrile, pimelonnitrile,suberonitrile, azelaonitrile, sebaconitrile, 1,20-eicosanedinitrile,acrylonitrile, allyl cyanide, crotononitrile, 3-pentene-l-nitrile,4-pentene-l-nitrile, 3-hexene-lnitrile, 2-hexene-l-nitrile,Z-heptene-l-nitrile, 3-octene-1- nitrile, IO-hendecene-l-nitrile,19-ei-cosene-l-nitrile, and the like.

As noted earlier in the even the R in R5CEN is substituted with cyano,alkoxycarbonyl or carbonyl the resultant nitrile should not be subjectto rapid homooligomerization or homopolymerization under the reactionconditions of the present invention. Generally nitriles in which theabove substituents are non-conjugated with or are at least two carbonatoms removed from the cyano group satisfy this requirement.

While pyridines can be detected in the product for reactions run at aslow as C., the present invention is usually practiced at temperatures inthe range of 200-600 C. Batch reactions are usually run at ISO-350 C.,and preferably at 200-350 C. Higher temperatures are operable but safetyconsiderations dictate the upper limit of 350 C. For flow processesemploying only short contact times, the temperatures may range up to 600C.

Reaction times may range from a few seconds under flow conditions athigh temperatures up to several hours at lower temperatures.

Ideally, an acetyleneznitrile ratio of 2:1 would be desirable, thisbeing the ratio in which the reactants combine to give pyridines. A highratio of acetylenemitrile, however, favors side reactions involvingacetylene polymerizations, so that a lower acetylenemitrile ratio,involving incomplete conversion of the nitrile, is usually desirable. Onthe other hand, where complete conversion of nitrile is desirable, as,for instance, in the conversion of dinitrile to a dipyridine, higheracetyleneznitrile ratios are indicated.

Generally, reactant ratios of acetylene:nitrile may be in the range1:100 to :1, the preferred ranges being from 1:50 to 2:1 for reactionsWhere total conversion of acetylene is desirable, and from 2:1 to 10:1for reactions where total conversion of nitrile is desirable.

Pressure is a minor variable in this process. Depending upon the natureof the acetylene components, the nature of the nitrile component, thesolvent, and the reaction temperature, superatmospheric pressure mightbe required to maintain reactants at sufficiently high concentration topromote reaction at a reasonable rate. The process is operable atsubstantially atmospheric pressure when the reactants are sufiicientlyhigh boiling. Generally, however, the pressure ranges from atmosphericto 3000 p.s.i. and preferably pressures from atmospheric to 1500 p.s.i.are employed.

The reaction is most conveniently run with no solvent, or with thenitrile component in excess as the only solvent, but any solvent,appropriately inert toward reactants, products, and catalysts, may beemployed. Such solvents would include aliphatic and aromatichydrocarbons, ethers, esters, and alcohols.

Products of this reaction may be isolated by standard procedures ofdistillation or of crystallization, where they are solid. Advantage maybe taken of their basic character to extract them into aqueous acid,from which they may be recovered by basification, and this method isespecially useful in aifording pure product, free from non-basic sideproducts, solvent, and reactants.

The reaction mixtures obtained in the following examples were analyzedby gas-liquid partition chromatography. The standard procedure employeda 6-ft. column packed with silicone gum nitrile on Gas Chrom RA with ahelium flow of 50 mL/min. at a temperature from 70-240 C. programmed toincrease at 16 C./min. The analysis in Example 21 was carried out at acolumn temperature of 240 C. and those of Examples 27-31 at a columntemperature of 160 C. Analyses of Examples 32-37 were carried out on asimilar column packed with 20% Carbowax 4000/Chromosorb W at a fixedtemperature of 150 C.

The product formed is reported as yield, based on the acetylene employedand calculated by the formula:

Moles product 100x 2 Percent yield: Moles acetylene (s) EXAMPLE 1Z-Methylpyridine From Acetylene and Acetonitrile in the PI 61166 of a)4]2 1o 12) 2] (A) Product identification-A Pyrex tube, containing 0.5 Of[(CH3)4N]2[CO(B10H12)2], was sealed uHdCI' nitrogen and was placed in a400-ml. stainless-steel shaker tube along with acetonitrile (60 ml.) Thetube was cooled and evacuated, 10 g. (0.385 mole) of acetylene wasadded, and the mixture heated, with shaking and under autogenouspressure, at 50 C. for 2 hours, at 120 C. for 2 hours, and at 200 C. for6 hours, the pressure reaching 540 p.s.i.g. at 200 C. and thendecreasing to 480 p.s.i.g. The tube was cooled and vented and thecontents were evaporatively distilled at room temperature and 1 pressureto yield crude condensate (41.3 g.) and a residue of black solid (0.4g.). Gas chromatography of the crude condensate revealed a majorcomponent at 7.2 minutes, in addition to peaks due to acetonitrile and atrace of benzene. The component at 7.2 minutes was isolated from theefiluent stream of the gas chromatograph in a Dry-Ice trap, diluted withcarbon tetrachloride, and examined by NMR and IR spectroscopy; bothspectra were identical with those of an authentic pure sample of2-methylpyridine.

(B) Yield-The reaction was run exactly as in (A), above, except that thetube was heated at 200 C. for 6 hours and at 250 C. for 6 hours, thepressure decreasing from 510 to 440 p.s.i.g. at 200 C., and from 720 to625 p.s.i.g. at 250 C. The tube contents were processed as in (A),above, to yield crude condensate (34.6 g.) and residue (1.0 g.). Knownweights of crude condensate (3.8 g.) and of dioxane (0.4 g.) were mixed,the mixture was subjected to gas chromatography, and the dioxane andZ-methylpyridine components in the effluent gas stream were caught inthe same Dry-Ice trap. The contents of the Dry-Ice trap were dilutedwith water and examined by NMR spectroscopy. Comparison of theintegrated area due to protons on 2-methylpyridine (236 units) with thatdue to protons on dioxane (331 units) permitted the calculation of yieldof Z-methylpyridine in crude condensate as 0.034 mole (3.2 g., 18% onacetylene charged).

EXAMPLE 2 2-Methylpyridine From Acetylene and Acetonitrile in thePresence of Cobalt(II) Dihydrobis(1-Pyrazolyl)Borate A Pyrex tube,containing 1.0 g. of

was sealed under nitrogen and placed in a 400-ml. stainless-steel shakertube along with acetonitrile (60 ml.). The tube was cooled andevacuated, acetylene (10 g., 0.385 mole) was added, and the mixtureheated, with shaking and under autogenous pressure, at 200 C. for 8hours, during which time the pressure decreased from 480-240 p.s.i.g.The tube was cooled and vented and the contents were evaporativelydistilled at room temperature and Lu. to yield crude condensate (44.6g.) and residue (3.0 g.). Gas chromatography of the crude condensaterevealed the presence of a major component at 7.1 minutes which wasidentified as 2-methylpyridine by enhancement of the peak height (andabsence of a new peak) when 2-methylpyridine was added to a sample ofthe crude condensate and the mixture was subjected to gas chromatographyunder identical conditions. For quantitative analysis, known weights ofcrude condensate (7.23 g.) and of dimethylformamide (0.80 g.) weremixed, the mixture was subjected to gas chromatography, and thedimethylformamide and 2-methylpyridine components in the eflluent gasstream were caught in the same Dry-Ice trap. The contents of the Dry-Icetrap were diluted with deuterium oxide and examined by NMR spectroscopy.The spectrum confirmed the identity of the product as 2-methylpyridine.Comparison of the integrated area of the spectrum due to protons ondimethylformamide (472 units) with that due to protons onZ-methylpyridine (596 units) permitted calculation of the yield of2-methylpyridine in crude condensate as 0.083 mole (7.9 g., 44% onacetylene charged).

EXAMPLES 3-16 Z-Methylpyridine From Acetylene and Acetonitrile in thePresence of Various Cobalt Catalysts The results of these examples aresummarized in Table I. In each case, the catalyst (0.5-1.0 g.) shown incolumn 1, sealed in a Pyrex tube under nitrogen, was placed in a 400 ml.stainless-steel shaker tube along with acetonitrile (60 ml.). The tubewas cooled and evacuated, 10 g. of acetylene added, and the mixtureheated, with shaking and under autogenous pressure, at 50 C. for 2hours, then at C. for 2 hours, then at 200 C. for 6 hours. The reactionmixtures were processed and analyzed as described in Example 2.

TABLE I IZ-methylpyridine from acetylene and aoetonitrile in thepresence of various cobalt catalysts] Example Percent No. Catalyst yield3 Co(NO)(CO)a 25 COz(CO)s 24 Co(acetylacetonate)z 20Co(acetylacetonate)a. 23 Co(acetate)z 5 Hg[Co(OO)1]z 24 [CHr-P (CtH5)2cool, CHz- (CaH5)2 CHaC=N cot1 cu15 31 0H= CH =N CO2(PHa)z(CO)7 19 a shli )al 2He)a]2i 34 15. 00 metal powder* 3 16 C0 0 28 *Reaction at 350 C.for 8 hours.

EXAMPLE 17 In a 400-ml. stainless-steel shaker tube was placed 1.0.

g. of

.ltQl...

L\ It 2 and acetonitrile (60 ml.). The tube was cooled and evac uated,20 g. (0.5 mole) of methylacetylene was added and the mixture heated,with shaking under autogenous pressure at 200 C. for 8 hours, duringwhich time the pressure decreased from 600 to 340 p.s.i.g. The tube wascooled and vented and the tube contents were rinsed out with a littleacetonitrile and evaporatively distilled at room temperature and Lu. toyield crude condensate (74.2 g.) and a black residue (3.0 g.). Gaschromatography of the crude condensate revealed major components at 8.9minutes and 9.1 minutes. These components were isolated from theefliuent stream of the gas chromatograph in separate Dry-Ice traps,diluted with deuterioacetone, and examined by NMR spectroscopy. The NMRspectrum of the 8.9 minute peak exhibited singlets at 3.737 (2 protons,3- and S-pyridine protons) and 8.207 (6 protons, 2- and 6-methylprotons), and 8.351- (3 protons, 4-methyl protons), and was consistentonly with 2,4,6-trimethylpyridine. The NMR spectrum of the 9.1 minutepeak exhibited doublets at 3.201- (1:7.0 c.p.s.) and 3.6l-r (1:7.0c.p.s.) (total of 2 protons, 3- and 4-pyridine protons), and singlets at8.191- (6 protons, 2- and 6-methyl protons) and 8.351- (3 protons,B-methyl protons); consistent with 2,3,6-trimethylpyridine. For infraredspectral analysis, the two components were isolated from the effluentstream of the gas chromatograph in separate Dry-Ice traps, and examinedas neat liquids. The infrared spectrum of the 8.9 minute peak wasidentical with that of an authentic sample of 2,4,6-trimethylpyridine;that of an authentic sample of 2,4,6-trimethylpyridine; that of the 9.1minute peak was consistent with its assigned structure as2,3,6-trirnethylpyridine.

For quantitative analysis, a portion of the crude condensate (10 g.) wasmixed with dimethylformamide (0.86 g.); this mixture was subjected togas chromatography and from the efiluent gas stream the two componentswere collected in a single Dry-Ice trap along with thedimethylformamide. The trap contents were diluted with deuterio- 8acetone and examined by NMR spectroscopy. Comparison of the integratedarea (114 units) due to the protons on the trimethylpyridines with that(64 units) due to the protons on dimethylformamide, permitted thecalculation of conversion of trimethylpyridines in the crude condensateas 0.103 mole. Comparison of the integrated area (68 units) due to thelow-field doublet with that (147 units) due to the low-field singletpermitted calculation of isomer distribution in the crude condensate.

Thus, there were produced 12.5 g. (0.103 mole) of trimethylpyridines(41% yield, based on methylacetylene) and these consisted of 68% of2,4,6-trimethylpyridine and 32% of 2,3,6-trimethylpyridine.

EXAMPLE 18 2,3,6-Trimethylpyridine From Acetylene, 2-Butyne andAcetonitrile in the Presence of Cobalt(II) Dihydrobis (l-Pyrazolyl)Borate In a 400-ml. stainless-steel shaker tube was placed 1.0

g. of catalyst,

2-butyne (37.5 g., 0.70 mole) and acetonitrile (60 ml.). The tube wascooled and evacuated, 10 g. (0.385 mole) of acetylene was added and themixture heated, with shaking under autogenous pressure at 200 C. for 8hours. During this time the pressure decreased from 740 to 420 p.s.i.g.The tube contents were evaporatively distilled at room temperature and 1to yield crude condensate (76.4 g.) and residue (4.0 g.). Gaschromatography of the crude, condensate revealed a major component at8.8 minutes, in addition to Z-methylpyridine. For qualitative analysis,this component was isolated from the effluent stream of the gaschromatograph and examined by NMR and infrared' spectroscopy; bothspectra were identical with those of 2,3,6-trimethylpyridine isolated inExample 17. For quantitative analysis, a portion (10 g.) of crudecondensate was mixed with dimethylformamide (0.80 g.) and the mixturewas subjected to gas chromatography as above. From the efiiuent stream,the 2 methylpyridine, 2,3,6-trimethylpyridine, and dimethylformamidecomponents were caught in a single Dry-Ice trap, and the trap contentswere diluted with deuterioacetone and examined by NMR spectroscopy.Comparison of the integrated area (502 units) due to the methyl protonsof dimethylformamide with that (663 units) due to the methyl protons ofthe pyridine components indicated a yield of 0.221 equivalents ofpyridine methyl groups. Comparison of the integrated area (42 units) dueto the 6-pyridine proton of 2,3,6-tritnethylpyridine, indicated aproduct distribution of 41 mole percent of Z-methylpyridine and 59 molepercent of 2,3,6-trimethylpyridine. Thus, the reaction produced 0.041mole (3.8 g., 21% yield on acetylene charged) of 2-methylpyridine, and0.060 mole (7.3 g., 16% yield on acetylene charged, 9% yield on Z-butynecharged) of 2,3,6-trimethylpyridine.

EXAMPLE 19 2-Ethylpyridine From Acetylene and Propionitrile (A) Productidentification.A Pyrex tube, containing 0.5 g. of [(CH N] [Co(B H wassealed under nitrogen and placed in a 400-ml. stainless-steel shakertube along with propionitrile (60 ml.). The tube was cooled andevacuated, 10 g. of acetylene was added and the mixture heated, withshaking under autogenous pressure at 200 C. for 8 hours, and then at 250C. for 8 hours. The pressure decreased from 460 to 400 p.s.i.g. at 200C., and from 640 to 610 p.s.i.g. at 250 C. The tube was cooled andvented, and the tube contents were removed and extracted with aqueoushydrochloric acid. The aqueous extract was made basic with sodiumhydroxide and the oil which appeared was extracted into dichloromethane.The dichloromethane extract was dried over potassium carbonate,filtered, and concentrated to small volume. Gas chromatography of theconcentrate revealed a major component at 7.6 minutes. This componentwas isolated from the efiiuent stream of the gas chromatograph and wasexamined by NMR and infrared spectroscopy. The NMR spectrum wasconsistent with 2-ethy1- pyridine, exhibiting multiplet absorption at1.96 to 2.037 (1 proton, 6-aromatic proton), 2.96 to 3.201- (1 proton,4-aromatic proton) and 3.45 to 3.68-r (2 protons, 3- and 5-aromaticprotons) and a quadruplet (J=7.4 c.p.s.) at 7.801- (2-protons, methyleneprotons) and a triplet (J=7.4 c.p.s.) at 9.331- (3 protons, methylprotons). The infrared spectrum was identical with that of an authenticsample of 2-ethylpyridine.

(B) Conversion.--A Pyrex tube, containing 0.5 g. of coba1t(II)dihydrobis(1-pyrazolyl)borate was sealed under nitrogen and placed in a400-ml. stainless-steel shaker tube along with propionitrile (60 ml.).The tube was cooled and evacuated, g. (0.385 mole) of acetylene wasadded and the mixture heated, with shaking under'autogenous pressure at200 C. for 8 hours. The tube was cooled and vented, and the tubecontents were evaporatively distilled at room temperature and 1,1. toyield crude condensate (39.0 g.) and residue (2.1 g.). Gaschromatography of the crude condensate revealed the presence of a majorcomponent at 8.2 minutes which was identified as 2-ethylpyridine byenhancement of the peak height (and absence of a new peak) when pure2-ethylpyridine was mixed with a portion of the crude condensate andsubjected to gas chromatography. For quantitative analysis, knownWeights of crude condensate (10.0 g.) and of dimethylformamide (0.58 g.)were mixed, the mixture was subjected to gas chromatography, and thedimethylformamide and 2-ethylpyridine components in the efliuent gasstream were collected in the same Dry-Ice trap. The contents of the trapwere diluted with deuterioacetone and examined by NMR spectroscopy. Thespectrum confirmed the identity of the product as 2-ethylpyridine.Comparison of the integrated area of the spectrum due to protons 0ndimethylformamide (210 units) with that due to the protons on2-ethylpyridine (159 units) permitted calculation of the yield of2-ethylpyridine in crude condensate as 0.0184 mole (1.97 g., 9.5% yieldon acetylene charged).

EXAMPLE 2-Ethylpyridine from Acetylene and Propionitrile in the Presenceof Co (CO) A Pyrex tube containing 1.0 g. of Co (CO) was sealed undernitrogen and was placed in a 400-ml. stainless-steel shaker tube, alongwith 60 ml. of propionitrile. The tube was cooled and evacuated, 10 g.(0.385 mole) of acetylene was added and the contents heated, withshaking under autogenous pressure at 120 C. for 2 hours (275 p.s.i.g.),160 C. for 2 hours (360 p.s.i.g.), and

200 C. for 6 hours (460 to 320 p.s.i.g.). The tube was cooled and ventedand the tube contents were processed as in Example 19 to yield 62.8 g.of crude condensate and 4.6 g. of residue. The crude condensate wasanalzed as in Example 19 and was found to contain 5.6 g. (0.053 mole,27% on acetylene charged) of 2-ethylpyridine.

EXAMPLE 21 2-Phenylpyridine From Acetylene and Benzonitrile in thePresence of Cobalt(II) Dihydrobis(1-pyrazo1yl)Borate tube contents wereconcentrated at room temperature and 1p. to yield condensate and residue(22.5 g.). The residue was evaporatively distilled at room temperatureand 0.01;]. to yield condensate (9.1 g.) and residue. Gas chromatographyof the condensate indicated that it consisted chiefly of a componentwith a retention time of 8.9 minutes. This component was collected fromthe eflluent gas stream of the gas chromatograph and was examined by NMRand infrared spectroscopy. The NMR spectrum was consistent with2-phenylpyridine, exhibiting multiplets at 2.03 to 2.221" (1 proton,6-pyridine proton), 2.51 to 2.611- (2 protons, 4- and S-pyridineprotons), 3,36 to 3.61-r (5 protons, phenyl protons), and 3.80 to 4.001-(1 B-pyridine proton). The infrared spectrum was identical with that ofan authentic sample of 2-phenylpyridine. This yielded 2-phenylpyridine(ca. 9.1 g.) (0.059 mole) 30% yield based on acetylene charged.

EXAMPLE 22 2-Propenylpyridines From Acetylene and Crotononitriles in thePresence of Cobalt(II) Dihydrobis(1-Pyrazolyl) Borate A Pyrex tube,containing 1.0 g. of cobalt(II) dihydrobis(1-pyrazolyl)borate, wassealed under nitrogen and placed in a 400-ml. stainless-steel shakertube along with crotononitrile (20 g., 69% sis-isomer, 31% trans-isomer)and 50 ml. of benzene. The tube was cooled and evacuated, 10 g. (0.385mole) of acetylene was added and the contents heated, with shaking underautogenous pressure at 200 C. for 8 hours. The tube was cooled andvented, and the tube contents were rinsed out with a little benzene andevaporatively distilled at room temperature and 0.01;. to yield crudecondensate (59.8 g.) and residue. The crude condensate was stirred withwater and titrated to the methyl orange endpoint with 6.67N hydrochloricacid (12.2 ml. required). The aqueous layer was separated, to it wasadded 17 ml. of 6.67N sodium hydroxide, and the resulting oil wasextracted with dichloromethane ml.). The dichloromethane layer was driedover potassium carbonate, filtered, and concentrated to small volume.Gas chromatography of the concentrate revealed the presence of twocomponents at 10.3 and 10.9 minutes, respectively. For qualitativeanalysis, each component was collected, separately, from the effluentstream of the gas chromatograph, diluted with deuterioacetone, andexamined by NMR spectroscopy. The 10.3 minute component showed a doublet(1:4 c.p.s.) at 1.941- (1 proton, 6-pyridine proton), a multiplet at2.52 to 2.941- (1 proton, 4-pyridine proton), a multiplet at 3.19 to3.501- (2 protons, 3- and S-pyridine protons), a multiplet at 4.15 to4.88-r (2 protons, olefinic protons), and a pair of doublets (J ,=8.6c.p.s., J =5.5 c.p.s.) at 8.477 (3 protons, methyl protons). The 10.9minute component showed a doublet (J =5 c.p.s.) at 2.081- (1 proton,6-pyridine proton), a multiplet at 2.83 to 3.081- (1 proton, 4-pyridineproton), a multiplet at 3.28 to 4.011 (4 protons, 3- and S-pyridineprotons and olefinic protons), and doublet (J=6.0 c.p.s.) at 8.771- (3protons, methyl protons). For the estimation of relative conversions,both the 10.3 and the 10.9 minute components were collected from theefliuent gas stream in the same trap, diluted with deuterioacetone, andexamined by NMR spectroscopy. By comparison of the relative areas underthe signals due to the methyl groups, it was concluded that of the totalsample, 32% consisted of the 10.3 minute component and 68% of the 10.9minute component. For examination by infrared spectroscopy, the twocomponents were collected separately from the effluent stream of the gaschromatograph and examined as neat liquids. The spectrum of the 10.3minute component was consistent with that of cis-2-propenylpyridine,exhibiting, among others, absorption at 794 and 699 cm.- (cis-CH -CH)and 743 cm.- (2-substituted pyridine); the spectrum of the 10.9 minutecomponent was consistent with that of trans-Z-propylpyridine, ex-

1 1 hibiting, among others, absorption at 968 cm. (trans- CH=CH) and 749cm.- (2-substituted pyridine. Thus, 2-propenylpyridines were produced at42% yield based on acetylene charged, and consisted of 32%cis-2-propenylpyridine and 68% trans-2-propenylpyridine..

EXAMPLE 23 2-Propenylpyridines From Acetylene and Allyl Cyanide in thePresence of Cobalt(II) Dihydrobis(1-Pyrazolyl) Borate A Pyrex tube,containing 1.0 g. of cobalt(II) dihydrobis(1-pyrazolyl)borate, wassealed under nitrogen and placed in a 400-ml. stainless-steel shakertube along with g. of allyl cyanide and 60 ml. of toluene. The tube wascooled and evacuated, 10 g. (0.385 mole) of acetylene was added and thecontents heated, with shaking and under autogenous pressure at 200 C.for 8 hours, during which time the pressure decreased from 550 to 245p.s.i.g. The tube was cooled and vented, and the tube contents wereevaporatively distilled at room temperature and 0.00 1,41 to affordcrude condensate (96.1 g.) and a blank residue (4.9 g.). Gaschromatographic analysis of the crude condensate showed the presence ofIrans-2-propenylpyridine (major) and cis-Z-propenylpyridine (minor) asthe only products, and also revealed a complete rearrangement ofunreacted allyl cyanide to a mixture of cisand trans-crotononitriles.This yielded propenylpyridines (4.0 g., ca. 0.037 mole); 19% yield basedon acetylene charged.

EXAMPLE 24 1,4-Bis(2-Pyridyl)Butane and 5 (2 Pyridyl)Pentanenitrile FromAcetylene and Adiponitrile in the Presence of Cobalt(II)Dihydrobis(1-pyrazoly1)Borate (A) Yield.In a 400-ml. stainless-steelshaker tube was placed 3.0 g. of Cobalt(II)dihydrobis(1-pyrazolyl)borate, 1.0 ml. of pyridine and 27.0 g. (0.250mole) of adiponitrile. The tube was cooled and evacuated, charged withacetylene, and heated at 200 C. for 18 hours. Pressure was maintained atca. 200 p.s.i.g. by periodic repressuring with acetylene, the totalacetylene amounting to 35.0 g. The tube was cooled and vented, and thetube contents were rinsed out with dichloromethane (100 ml.). Thedichloromethane solution was filtered, and the filtrate was stirred with300 ml. of water and 80 ml. (0.96 mole) of concentrated hydrochloricacid. The aqueous layer was drawn off and extracted with dichloromethaneuntil the extracts were nearly colorless. To the aqueous layer was addedg. (1.12 mole) of sodium hydroxide, and the oil which appeared wasextracted into 100 ml., and then ml. of dichloromethane. Thedichloromethane extracts were combined, dried over potassium carbonate,filtered, and evaporated at the water pump to yield crude basic product(30.7 g.) as a black oil. This oil was chromatographed on silicic acid(1200 g.). 5-(2-Pyridyl)pentanenitrile was eluted with 3:1 etherzacetoneand, after evaporation of solvent on the water pump, amounted to 11.7 g.(29% on adiponitrile) as a dark oil which exhibited an infrared spectrumidentical with that of the analytical sample. 1,4-Bis(2-pyridyl)butanewas eluted with 1:1 etherzacetone and, after evaporation of solvent onthe water pump, amounted to 11.5 g. (22% yield based on adiponitrile) asan off-white solid which, after recrystallization from pentane, affordedgood quality product (11.0 g.), m.p. 4647 C., which exhibited aninfrared spectrum identical with that of the analytical sample.

(B) Identification of 5-(2-pyridyl)pentanenitrile.Fr0m another run,conducted and processed as in (A) above, was obtained a crude basicfraction which was chromatographed on alumina (Woelm basic alumina,activity I). 5-(2-Pyridyl)pentanenitrile was eluted with 5% of methanolin dichloromethane, and was obtained as a pale yellow oil by evaporationof solvent. Evaporative distillation of this material at roomtemperature and 0.001

afforded the analytical sample of 5-(2-pyridyl)pentanenitrile as acolorless oil.

Analysis.-Calcd. for C' H N C, 74.96; H, 7.55; N, 17.49. Found: C,75.01; H, 7.56; N, 17.64.

The NMR spectrum (neat sample, external tetramethylsilane reference)exhibited a multiplet at 1.71 to 1.821 (1 proton, 6-pyridine proton), amultiplet at 2.60 to 2.881 (1 proton, 4-pyridine proton), a multiplet at3.15 to 3.331 (2 protons, 3- and S-pyridine protons), triplets at 7.57(1:70 c.p.s.) and 7.971 (J=6.5 c.p.s.) (total of 4 protons, terminalmethylene protons), and a multiplet centered at 8651 (4 protons, centralmethylene protons). The infrared spectrum (neat sample) was consistentwith the assigned structure, exhibiting absorption, among others, at3065 and 3020 cm.- (aromatic OH), 2960 and 2885 cm." (saturated OH),2240 cm.- (CEN), 1590, 1570 and 1475 cm. (aromatic unsaturation) and 760cm. (2-substituted pyridine). The ultra violet spectrum ethanol) wastypical for a 2-substituted pyridine with 2680 A. (e=2720), 2620 A.(e=3680), and 2570 A. (6:3170).

(C) Identification of 1,4-Bis(2-Pyridyl)Butane.From another run,conducted and processed much as in (A) above, was obtained crude1,4-bis(2-pyridyl)butane as a tan solid. A single recrystallization ofthis material from pentane afforded the analytical sample of 1,4-bis(2-pyridyl)butane as chunky white crystals, m.p. 4748 C.

The NMR spectrum (carbon tetrachloride, external tetramethylsilanereference) exhibited a multiplet at 1.68 to 1.801 (2 protons, 6-pyridineprotons), a multiplet at 2.58 to 2.861 (2 protons, 4-pyridine protons),a multiplet at 3.11 to 3.251 (4 protons, 3- and S-pyridine protons), amultiplet centered at 7.421 (4 protons, external methylene protons), anda multiplet centered at 8.401 (4 protons, central methylene protons).The infrared spectrum (potassium bromide wafer) was consistent with thestructure, exhibiting absorption, among others, at 3060 and 3010 cm.(aromatic C-H), 2960 and 2860 cm? (aliphatic OH), 1585, 1565, and 1475cm." (aromatic unsaturation) and 748 cm. (Z-substituted pyridine). Theultraviolet spectrum (95% ethanol) was typical for a 2-substitutedpyridine with 7mm 2680 A. (e=6660), 2620 A. (6 8650), and 2570 A. (e-7280).

EXAMPLE 25 Trimethylpyridines From Methylacetylene and Acetonitrile inthe Presence of Cobalt(II) Dihydrobis(1-Pyrazolyl)Borate Eflect oftemperature on yield.-The reaction between methylacetylene andacetonitrile was conducted exactly as in Example 17, except that thetemperature of the reaction was 300 C., and as a result the pressuredecreased from 780 to 660 p.s.i.g. The reaction mixture was processedand analyzed exactly as in Example 17. The trimethylpyridines amountedto 17.7 g. (0.146 mole, 58% yield, based on methylacetylene) and wascomposed of 70% of 2,4,6- trimethylpyridine and 30% of2,3,6-trimethylpyridine. Thus, a higher temperature increased the yieldof trimethylpyridines without affecting the isomer distribution.

EXAMPLE 26 Trimethylpyridines From Methylacetylene and Acetonitrile inthe Presence of Cobalt(II) Dihydrobis(1-Pyrazoly1')Borate Effect ofpressure on yield-The reaction between methylacetylene and acetonitrilewas conducted exactly as in Example 17, except that 60 g. (1.5 moles) ofmethylacetylene was employed, and as a result the pressure decreasedfrom 1080 to 770 p.s.i.g. The reaction mixture was processed andanalyzed exactly as in Example 17. The trimethylpyridines amounted to17.1 g. (0.142 mole, 18.9% yield, based on methylacetylene) composed of72% of 2,4,6-trimethylpyridine and 28% of 2,3,6-trimethyl- 13 pyridine.The increased pressure of methylacetylene enhanced the amount ofpyridines obtained.

EXAMPLES 27-31 2-Methylpyridine From Acetylene and Acetonitrile in thePresence of Cobalt(III) Acetylacetonate Effect of temperature on theyield.The results of these experiments are summarized in Table II. Ineach case, 1.0 g. of cobalt(III) acetylacetonate was sealed in a Pyrextube under nitrogen, placed in a 400-ml. stainless-steel shaker tubealong with 60 ml. of acetonitrile. The tube was cooled and evacuated, g.of acetylene added and the mixture heated, with shaking and underautogenous pressure at the indicated temperature for 8 hours. Thereaction mixtures were processed as described in Example 2. Quantitativeanalyses were by gas chromatography of the crude condensates; peakheights of the 2-methylpyridine components were compared with acalibration curve, obtained from standard mixtures of Z-methylpyridinein acetonitrile. Yields were calculated on the basis of acetylenecharged.

TABLE II Efieet of temperature on the yield of Z-methylpyrldlne fromacetylene and acetonitnle in the presence of eobalt(III)acetylacetonatel EXAMPLES 32-37 2-Methylpyridine From Acetylene andAcetonitrile in the Presence of Cobalt(III) Acetylacetonate Efiect ofchelating ligands on the yield.The results of these experiments aresummarized in Table III. In each case, 1.07 g. (3.0 mmoles) ofcobalt(HI) acetylacetonate was sealed in a Pyrex tube under nitrogen,and ligand, similarly encapsulated, was placed in a 400-ml.stainlessstele shaker tube along with 60 ml. of acetonitrile. The tubewas cooled and evacuated, 10 g. of acetylene added and the mixtureheated, with shaking and under autogenous pressure at 250 C. for 8hours. The reaction mixtures were processed as described in Example 2.Quantitative analyses were by gas chromatography of the crudecondensate; peak heights of the Z-methylpyridine components werecompared with a calibration curve obtained from standard mixtures ofZ-methylpyridine in acetonitrile. Yields were calculated on the basis ofacetylene charged.

TABLE III [Effect of chelating ligands on yield of Z-methylpyridlne fromacetylene tandgalpetonlitrile in the presence of coba1t(III)acetylacetonate at 250 C.

or ours Yiell Example Mmole Mmole (per- No. Co(C H O2)3 Ligand ligandcent) 3. 0 on 3d EXAMPLE 3 8 The procedure of Example 3 was followed,using the catalyst.

1 4 2-Methylpyridine, formed in 22% yield, was identified as describedin preceding examples.

Preparation of Catalysts Catalysts used in the preceding examples wereprepared according to directions given in the following references or bythe specific procedures not yet published.

Examples 1, 10, 19.F. Klanberg, P. A. Wegner, G. W. Parshall, E. L.Muetterties, Inorg. Chem., 7, 2072 (1968).

Examples 2, 17, 18, 21, 22, 23, 24, 25, 26.S. Trofimenko, J. Am. Chem.Soc., 89, 3170 (1967).

Example 3.-F. Seel, Z. Anorf. Allgem. Chem., 269, 40 (1952).

Examples 4-7, 20, 2737.-Commercial products.

Example 8.R. B. King, Organometallic Synthesis, 1, 101 (1965).

Example 9.--E. M. Thorstein, F. Basolo, J. Am. Chem. Soc., 88, 3939(1966).

Example 11.M. Iwamoto, S. Yuguchi, Bull. Soc. Chem. Jap. 41, 150 (1968).

Example 12.G. N. Schrauzer, R. J. Windgassen, J. Am. Chem. Soc. 88, 3738(1966).

Example 13.Co (CO) (PH Dicobalt octacarbonyl (6.8 g., 0.020 mole) in ml.of ether was reacted with phosphine at room tempera ture. The blacksolid C0 (C0) (PH (3.9 g.) precipitated. This was filtered ed and washedwith acetone. The infrared spectrum of the product showed P-H absorptionat 2300 cmf broad unresolved CO absorption at 1960 cmr a sharp band at1080 cm. (probably a P-H bending mode), and a broad band at 780 cm.- Itwas incompletely soluble in pyridine and dimethylformamide, insoluble inother solvents.

Analysis.-Calcd. for Co (CO) (PH C, 22.0; H, 1. 6: O, 29.3; P, 16.2; C0,30.9. Found: C, 21.0; H, 1.9; O, 29.3; P. 15.1; C0, 31.4.

Example 14.W. Hieber and W. Freyer, Chem. Ber., 93, 462 (1960).

Examples 15, 16.Commercial products.

Example 3 8.lPreparation of s a' a' z 'l s 2] 2 (A) Preparation of [(CHPOH OH P (CH CoBr In a nitrogen atmosphere, 4.7 g. (0.0312 mole)[prepared as described by G. W. Parshall, J. Inorg. Nucl. Chem., 14, 291(1960)] was added to a solution of CoBr (3.3 g., 0.0151 mole) in ml. oftetrahydrofuran. The blue-green solution rapidly deposited abrownish-red crystalline solid. The mixture was heated for 15 minutes to45 C., cooled and the solid collected. Drying at 70 C./ 0.2, for 16hours gave 6.4 g. (80%) of brown-red which decomposes at 380 C.

Analysis.-Calcd. for C H Br CoP C, 27.8; H, 6.2; Br. 30.7. Found: C,27.7; H, 6.3; Br, 30.3.

The solid is slowly decomposed upon air exposure.

(B) Preparation of ['('OH PCH CHgP'(CH Co solution.--All manipulationswere performed in a dry nitrogen atmosphere. A mixture of naphthalene(5.6 g., 0.0437 mole) and sodium chips (1.7 g., 0.0738 g. atom) in 75ml. of tetrahydrofuran was stirred at room temperature for 2.5 hours togive a dark green solution of NaC H This solution was then added inportions to a suspension of (CH 'PCH CH P(CH CoBr prepared as in (A).The green color of the Nac H solution was rapidly dischaged to give adark brown-red solution containing a brown solid. This solution wasfreshly prepared before each experiment. The exact nature of the 1 5reduction product is unknown and will be referred to as 3 z z z i' a z]2 Preparation of 2PCH2CH2P 2] ZCOH from PCHgCHzP CH3 2] 2CD and H20.-Asolution of (CH POH CH P(CH C0 was prepared as in (B) from 5.0 g.(0.0333 mole) of 3.5 g. (0.0160 mole) of CoBr 6.2 g. (0.0483 mole) ofnaphthalene, and 2.7 g. (0.117 g. atom) of sodium. Addition of H 0 (0.31g., 0.0171 mole) to the resulting redbrown solution caused the color torapidly change to brown-yellow. After warming to 40 C. "for 0.5 hour,the solvent was removed under vacuum, the residue extracted withpetroleum ether (300 ml.), the extracts evaporated under vacuum andnaphthalene removed from the orange residue at 30 'C./0.5 .t. Theresulting product was sublimed at 90 C./0.6/L to give 3.7 g. (64%) ofyellow, crystalline [(CH PCHzCH P(CH CoH, mp. 9910l C. An analyticalsample was prepared by recrystallization from petroleum ether at -78 C.followed by two additional sublimations.

Analysis.Calcd. for C H Co'P C, 40.0; H, 9.2; Co, 16.4; P. 34.4. Found:C, 39.6; H, 9.4; Co, 15.6; P, 34.5.

The product is a pyrophoric solid, soluble in petroleum ether, benzeneand tetrahydrofuran. The infrared spectrum (Nujol mull) shows a Co-Hstretching frequency at 1855 cm.- The proton nmr spectrum shows thehydride resonance at +17.8 p.p.m. in tetrahydrofuran and at +23.4 p.p.m.in C H solution (relative to internal Both resonances are observed asbroad triplets with J -25 c.p.s. but are believed to actually bequintets based on the relative intensities.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows: i

1. A process for the preparation of substituted pyridines comprisingcontacting at about 150 C. to 600 C., a nitrile of the formula R5-CEN,wherein R is alkyl, alkenyl or aryl of up to 20 carbon atoms and may besubstituted with cyano, alkoxycarbonyl, and acetyl provided that theresultant nitrile is not subject to rapid homooligomerization orhomopolymerization under the reaction conditions,

with at least one acetylenic compound of the formula R -CEC-R wherein Rand R are selected from hydrogen, alkyl of up to carbons, alkenyl of upto 10 carbons, aralkyl of up to 10 carbon atoms or alkoxy of up to 12carbon atoms, provided that said acetylenic compound is not subject torapid homooligomerization or homopolymerization under the reactionconditions, in the presence of a cobalt catalyst selected from the groupconsisting of cobalt metal cobalt oxide simple cobalt salts selectedfrom the group consisting of acetate, formate, citrate, tartratelpropionate, fluoride, chloride, bromide, iodide, nitrate, sulfate,stearate and naphthenate;

cobalt complexes in which the cobalt has 2 or 4 to 16 6 coordinatingsites occupied by ligands selected from the group consisting of (i)hydrogen [1], i

(ii) alkyl of up to 8 carbon atoms [1],

(iii) carbonyl [4],

(iv) nitroso [1], l

(v) phosphine ligands [4] selected from the group consisting ofphosphine, trimethylphosphine, triethylphosphine, tripropylphosphine,dimethylphenylphosphine, diethylphenylphosphine, ethyldiphenylphosphine,triphenylphosphine, 1,2-ethylene-bisdiethylphosphine,1,2-ethylene-bis-dimethylphosphine, and1,2-ethylene-bis-diphenylfphosphine,

(vi) dodecahydrodecaborate [2],

(vii) enolates of fl-keto esters [3] selected from the group consistingof ethyl acetoacetate, ethyl Z-methyl-acetoacetate, methyl acetoacetate,ethyl benzoylacetate, ethyl fi-ketopropionate, and ethylfi-ketovalerate,

(viii) enolates of 1,3-diket0nes [3] selected from 'the group consistingof acetylacetone, propionylacetone, benzoylacetone, dibenzoylmethane,1,1- dibenzoylethane, 3-methyl-2,4-pentanedione, and 2,4-hexanedione,

(ix) bis(pyrazolyl)borates [2] selected from the group consisting ofdihydrobis (pyrazolyl borate, dicthylbis(pyrazolyl)borate, dipropylbis(pyrazolyl borate, and diphenylbis(pyrazolyl)borate, and

(X) glyoximate ligands [2] selected from the group consisting ofglyoxime, dioxime of dimethylglyoxal, dioxime of furil, dioxime ofbenzil,

with the proviso that the number of ligands linked to each catalyst atomdoes not exceed the bracketed number following each ligand class,

wherein when the combination of cobalt and ligand results in an anion,the counter-ion is selected from alkali metal, alkaline-earth metal, Cu,Cd, Zn+ Pb+ Sn, Hg, and tetra(lower alkyl)ammonium, and

when the combination of cobalt and ligand results in a cation, thecounter-ion is selected from halogen and B(CSH5)4.

2. The process of Claim 1 wherein R and R are selected from hydrogen,alkyl or alkenyl of up to 6 carbon atoms.

3. The process of Claim 1 wherein R is alkyl, alkenyl or aryl of up to 8carbon atoms.

4. The process of Claim 1 wherein the nitrile and acetylenic reactantsare contacted in a batch process at about 200 C.350 C. i

References Cited UNITED STATES PATENTS 1,421,743 7/1922 Stuer et a1. 260290 3,264,307 8/1966 Jones 260-290 HARRY I. MOATZ, Primary Examiner US.Cl. X.R.

